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onsemi 74VHCT244ASJX
- Part No.:
- 74VHCT244ASJX
- Manufacturer:
- onsemi
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
74VHCT244ASJX.pdf
- Description:
- IC BUFFER NON-INVERT 5.5V 20SOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,399
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Product details
Overview
74VHCT244ASJX from ON Semiconductor is an octal non-inverting 3-STATE buffer/line driver with two active-low output enables (OE1, OE2), designed for memory address driving, clock distribution, and bus-oriented data transmission in 5V TTL-compatible systems. It operates from 4.5V to 5.5V, delivers 8mA output drive, achieves 5.9ns typical propagation delay at 5V, and supports 3V–5V mixed-voltage interfacing.
For engineers reviewing the 74VHCT244ASJX datasheet, pinout, applications, or equivalent options, key selection criteria include 3-STATE timing (tPZL/tPLZ ≤ 13.5ns), input/output voltage tolerance up to 7V, low ICC of 4µA max at 25°C, and EIAJ TYPE II SOP-20 (M20D) package compatibility.
Technical Context
The 74VHCT244ASJX implements dual-gated 3-STATE control logic: OE1 enables outputs O0–O3, OE2 enables O4–O7 - both active-low and independently controllable. Its silicon gate CMOS process ensures TTL-level input thresholds (VIH = 2.0V min, VIL = 0.8V max) while maintaining CMOS power efficiency.
Input and output protection circuits allow safe operation across mismatched supply domains: inputs tolerate –0.5V to +7.0V regardless of VCC, and outputs withstand –0.5V to VCC+0.5V in active state or –0.5V to +7.0V in 3-STATE (OFF), enabling robust 5V-to-3V system interfacing without external level shifters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V to 5.5V - ensures compatibility with standard 5V TTL logic rails and margin for ripple/noise. |
| Propagation Delay | 5.9ns typical (CL = 50pF, VCC = 5V) - enables reliable operation in high-speed address/data buses up to ~100MHz. |
| Output Drive | ±8mA - sufficient to drive 50pF loads with <1ns skew and meet TTL fan-out requirements. |
| Quiescent Current | 4µA max at TA = 25°C - supports low-power standby modes in battery-backed or energy-sensitive systems. |
| Input Voltage Range | –0.5V to +7.0V - allows direct connection to overvoltage-tolerant microcontrollers or legacy 5V peripherals without clamping diodes. |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded control and automotive under-hood auxiliary modules. |
Pinout & Package
74VHCT244ASJX is packaged in a 20-lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm wide (Package Number M20D), with standard 1.27mm pitch and gull-wing leads suitable for reflow soldering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE1, OE2 | Active-low 3-STATE enable inputs - independent control of lower/upper quad outputs; pulled HIGH disables all outputs to high-impedance. |
| 2–9, 11–18 | I0–I7, O0–O7 | Non-inverting buffered I/O pairs - inputs I0–I3 map to outputs O0–O3 (OE1-controlled); I4–I7 map to O4–O7 (OE2-controlled). |
| 10 | GND | Ground reference - must be connected to system common; decoupling capacitor required within 1cm. |
| 20 | VCC | Positive supply - bypassed with 0.1µF ceramic capacitor directly to GND to suppress switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| Pin & function compatibility with 74HCT244 | Enables drop-in replacement in existing HCT-based designs without layout or firmware changes. |
| Power-down input/output protection | Prevents latch-up or damage when VCC = 0V or during hot-insertion - inputs/outputs tolerate –0.5V to +7.0V regardless of supply state. |
| Low dynamic power dissipation | CPD = 18pF - limits switching current to ~0.9mA at 10MHz, reducing thermal load in dense PCB layouts. |
| High noise immunity | VINH = 2.0V min / VIL = 0.8V max - provides >1.2V noise margin against TTL-compatible signals in electrically noisy environments. |
Applications
| Memory Address Buffering | Clock Distribution Network |
|---|---|
Use Scenario: Driving 16-bit address bus from microcontroller to SRAM or Flash memory in industrial PLCs. IC Role / Device Role / Timing Role: Non-inverting 3-STATE buffer isolating CPU address lines from memory load; OE pins synchronized to memory enable strobes. Use Value: Prevents bus contention during DMA cycles and reduces capacitive loading on CPU outputs by >60%, improving signal integrity at 20MHz. | Use Scenario: Distributing a 25MHz system clock to multiple peripheral ICs (UART, ADC, GPIO expanders) on a single PCB. IC Role / Device Role / Timing Role: Fan-out buffer with matched tPLH/tPHL (≤1ns skew) ensuring synchronous edge arrival across all destinations. Use Value: Eliminates clock skew-induced setup/hold violations and enables deterministic timing margins of ≥1.5ns at 25MHz. |
| Bus Transceiver Interface | Mixed-Voltage System Bridge |
Use Scenario: Bidirectional data transfer between 5V microcontroller and 3.3V sensor hub via shared parallel bus. IC Role / Device Role / Timing Role: Unidirectional line driver (configured as transmit-only path) with 3-STATE control coordinated by direction signal. Use Value: Enables clean bus release during idle periods and prevents back-driving of 3.3V receivers by 5V logic levels. | Use Scenario: Interfacing legacy 5V FPGA I/O banks to modern 3V SPI flash memory in aerospace avionics modules. IC Role / Device Role / Timing Role: Level-shifting buffer with rail-to-rail input tolerance - accepts 5V signals while driving 3V-compatible loads safely. Use Value: Removes need for discrete resistor dividers or dedicated level translators, saving 3.2mm² PCB area per channel. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-STATE buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT244N | Dual OE inputs; identical AC/DC specs but offered in PDIP-20 (not surface-mount); no Pb-free default. | Suitable for through-hole prototyping or legacy repair; lacks tape-and-reel packaging for automated assembly. | Select when manual soldering or DIP socket use is required; verify JEDEC MS-001 vs EIAJ TYPE II footprint compatibility. |
| 74LCX244MTCX | Lower VCC range (2.0–3.6V); higher speed (tPD = 4.5ns typ); 3.6V-tolerant inputs - not 5V-compatible. | Designed for 3.3V-only systems; cannot replace 74VHCT244ASJX in 5V environments without level shifting. | Choose only for new 3.3V designs requiring sub-5ns timing; incompatible with 5V supply or TTL input thresholds. |
Compared with SN74HCT244N and 74LCX244MTCX, the 74VHCT244ASJX uniquely balances 5V TTL compatibility, surface-mount SOP-20 packaging, Pb-free compliance, and industrial temperature range - making it optimal for volume-manufactured 5V embedded controllers where reliability and RoHS compliance are mandatory.
Availability
74VHCT244ASJX is available at Aetrix Electronics and suitable for memory address buffering, clock distribution networks, and mixed-voltage system bridging requiring stable component supply across industrial, automotive, and communications equipment programs.
Supply support for 74VHCT244ASJX includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
ON Semiconductor (formerly Fairchild Semiconductor) is a global leader in intelligent power and sensing technologies, serving automotive, industrial, cloud computing, and IoT markets with energy-efficient semiconductor solutions.
The 74VHCT244ASJX belongs to ON Semiconductor's VHCT logic family - engineered for high-speed, low-power 5V TTL-compatible interfacing in space-constrained industrial control and telecom infrastructure applications.
FAQ
What is the maximum operating frequency supported by the 74VHCT244ASJX?
The 74VHCT244ASJX does not specify a maximum clock frequency in its datasheet, as it is a combinational buffer-not a clocked device. However, its 5.9ns typical propagation delay (CL = 50pF, VCC = 5V) supports reliable operation in data/address paths up to approximately 100MHz, assuming proper PCB layout, termination, and load capacitance ≤50pF. Signal integrity validation remains the responsibility of the end-user design team.
Does the 74VHCT244ASJX support hot-swap or live-insertion?
Yes, the 74VHCT244ASJX supports hot-swap conditions due to its input/output protection circuitry: inputs and outputs tolerate –0.5V to +7.0V independent of VCC state, and outputs enter high-impedance when VCC = 0V. This prevents damage during insertion into powered backplanes or live 5V buses, provided current limits (±25mA per pin, ±75mA total) are respected.
Can the 74VHCT244ASJX drive a 100pF load reliably?
The 74VHCT244ASJX is characterized for CL = 15pF and 50pF loads; performance at 100pF is not guaranteed. At higher capacitance, propagation delay increases (e.g., tPLH may exceed 12ns), and output rise/fall times degrade, risking timing violations. For 100pF loads, derate VCC to 5.5V, verify waveform integrity with oscilloscope measurement, and consider adding series termination or using a higher-drive buffer like 74VHCT244ASJX's 16mA variants if available.
Is the 74VHCT244ASJX pin-compatible with the 74VHCT244AM?
No - the 74VHCT244ASJX (EIAJ TYPE II SOP-20, M20D) and 74VHCT244AM (JEDEC MS-013 SOIC-20, M20B) share identical pin numbering and electrical functionality but differ in package dimensions: SJX is 5.3mm wide with 1.27mm pitch; AM is 7.5mm wide with same pitch. They are not mechanically interchangeable without PCB redesign, though schematic symbols and netlists remain identical.
What is the purpose of the two separate output enable pins (OE1 and OE2) on the 74VHCT244ASJX?
The dual OE pins (OE1 for O0–O3, OE2 for O4–O7) allow independent 3-STATE control of two groups of four outputs. This enables partial bus isolation - for example, disabling only memory address bits A0–A3 while keeping A4–A7 active during bank-switching operations - reducing system-level contention and simplifying timing-critical control sequences in multi-peripheral architectures.
74VHCT244ASJX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74VHCT
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Non-Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 4
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 8mA, 8mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOP
74VHCT244ASJX FAQ
1.How can I place an order for 74VHCT244ASJX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74VHCT244ASJX on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for 74VHCT244ASJX reliable?
The price and inventory of 74VHCT244ASJX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74VHCT244ASJX is usually 5 days.
3.What payment methods are accepted for 74VHCT244ASJX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74VHCT244ASJX transactions.
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4.How is shipping managed for 74VHCT244ASJX?
74VHCT244ASJX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74VHCT244ASJX order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for 74VHCT244ASJX?
For technical support, including 74VHCT244ASJX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74VHCT244ASJX requirements.
6.How does Aetrix verify that 74VHCT244ASJX is sourced from the original manufacturer or authorized distributors?
All 74VHCT244ASJX products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 74VHCT244ASJX meets industry standards.
7.What is the process for return or replacement of 74VHCT244ASJX?
All 74VHCT244ASJX units undergo pre-shipment inspection (PSI). If there is an issue with 74VHCT244ASJX, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The 74VHCT244ASJX part is unused and in its original packaging.
Return procedure for 74VHCT244ASJX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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